Eddy current track braking apparatus



'AUGUST MEYER,

Patented .luly 18, 1933 .UNITED s'rArus carica 0F BERLIN-SCHONEBERG, GERMHZ, ASSEGNO?, TO SLWENS- SCHUCKERTWERKE AKTIENGESELLSCHAFT, 0F BERLIN-SEIHENSSTADT, GERMANY,

This invention relates to marshalling or hump yards for railway vehicles in which individual cars or groups of cars are distributed and collected to form trains by cansing the cars to travel under their own momentum usually along inclined tracks connected by means of switches controlled from a suitable point.

In marshalling yards of this character it is usual to provide track braking apparatus at suitable points along the tracks so as to enable the speed of travel of the cars to be controlled and determined as desired regardless of their running resistance which is generally different for different cars. During marshalling it is often required that single cars following one another along a track leading over a switch to two divergent tracks should be caused to pass on to one or other of the tracks by operating the switch between the passage of the several cars over the switch and it is obviously desirable in `,rder to avoid delay that the distance separating the cars should be maintained approximately uniform and should not be greater than is necessary to enable the switch to be properly operate In order to maintain a suitable speed and spacing apart ofthe cars the braking apparatus must evidently be capable of rapidly and effectively reducing the speed of. any car as desired and for this purpose braking apparatus of the eddy current type is particularly suitable as the braking effort exerted thereby is more rapidly built up to its full value than is the case with other types of brakes.

It will be understood however that any delay in the braking action necessarily requires that a corresponding interval between successive cars must be maintained in order to give effective control and the greater this interval the less efficiently the total trackway of the yard is utilized.

The present invention accordingly has for its object to provide means for decreasing the 'time interval between the initiation by the operatorof the braking action of eddy current braking apparatus and the establishment of the full desired braking effort.

BEARING APPIRTUS 658,723, and in Germany February 2'?, 1932.

The invention is illustrated by way of cirample in the accompanying drawing of which Figures 1 and 2 are diagrammatic views of brake controlling apparatus embodying different forms of the invention.

Figure 3 being a curve diagram illustrating the operation of the apparatus of Figure 2 i Referring now first to the apparatus shown in Figure l it will be seen that the energizing winding l of the eddy current track brake is shown as supplied with rectified current from an alternating supply circuit 5 through a rectifier' 3 and a transformer 4. Owing to the high self induction of the brake winding 1, the current therein only increases slowly when the electro-magnetically operated switch 6 is closed by closing the operators control switch 2 and consequently a considerv able interval of time elapses before the eddy current brake develops its full braking effort. i

According to the present invention the energization of the brake winding 1 is arranged to be increased above its normal operating value when the switch 6 is first closed, this being effected by providing a choke coil 7 connected in series with the rectifier 3, and

adapted to be shunted by an electro-magnetically operated switch 8, which is energized simultaneously with the switch 6 when the control switch 2 is closed.

An electro-magnetically operated control device 9 is provided, having an energizing winding connected in the circuit of the brake winding l and having contacts connected in the energizing circuit of the switch 8.

ln operation, when the operator closes the control switch 2 in order to render the brake operative the switch 6 is closed to complete the circuit of the brake winding l and simultaneously the switch 8 is closed to short circuit the choke coil 7 with the. result that the current traversing the brake winding l corresponds to the full voltage supplied from the transformer 4 through the rectifier 3. As soon as this current has attained its full working value the control device 9 opens its contacts and deenergizes the switch 8 so that the choke coil 7 is reinserted into the circuit of the brake winding 1 and the current traversing this winding is maintained at its corresponding working value.

It will thus be seen that the voltage initially impressed upon the brake winding 1 when the switch 2 is closed is greater than the nor. mal working value so that the current in the winding 1 rapidly builds up to its full work ing magnitude and the brake consequently ra idly attains it-s full braking effort.

igure 2 illustrates a modified arrangement in which the development of full braking effort is accelerated differently for different degrees of braking effort.

In this case the choke coil 7 of the arrangement of Figure 1 is replaced by a number of choke coils 71, 72 and 73 connected in series with one another in the circuit of the brake replaced by a controller winding l. The choke coils 72 and 73 are adapted to be short-circuited by switches 82 and 83 respectively while a switch 81 is ada ted to short-circuit all the choke coils 71, 2, 73 simultaneously.

The rate of increase of current in the brake winding 1 under dilerent conditions of operation is shown in the curve diagram of Figure 3 in which the horizontal ordinates represent time and the vertical ordinates represent the current in the brake winding.

The rate of rise of this current which would occur if the invention were not utilized, is shown in dotted lines in each case.

The operators control switch 2 shown in igure 1 is in the arrangement of Figure 3 20 adapted to be set into one or other of three operative positions indicated at I, II and III. The control device 9 is in this arrangement provided with an energizing winding 91 connected in the circuit of the brake winding l and two auxiliary windings 92 and 93 the circuits of which are controlled by the controller 20.

The operation of the apparatus is as follows:

If the controller 2O is moved to the operative position I, the energizing winding of the switch 81 is supplied with current through the controller 20 and the closed contacts of the control device 9 so that the choke coils 71, 72 and 73 are short-circuited. Simultane ously the energizing winding of the switch 6 is supplied with current in series with the winding 93 and the winding 92 is also energized.

The switch 6 is thus closed and full voltage is supplied to the brake winding 1. As soon as the current traversing the winding 1 attains the value J1 (Figure 3) the control device 9 breaks the circuit of the energizing winding of the switch 81 which thus opens and reinserts the choke coils 71, 72, 73 into the circuit of the winding 1.

When the controller 20 is moved to its operative position II, the switches 81 and 82 are initially closed and since the winding 93 is deenergized in this position of the controller 20, the control device 9 will not be operated to deenergize the switch 8l until the current traversing the brake windin 1 has attained the higher value J2 (Figure 3.

When the controller 20 is moved to the position III the switches 81, 82 and 83 are all initially closed and since both the windings 92 and 93 are deenergized in this position of the controller 20, the switch 81 will not again be opened until the current traversing the brake winding l and the winding 91 of the contr)ol device 9 attains the value J3 (Figure 3 The invention is evidently not limited to the particular arrangements above described and illustrated by way of example and various modifications may obviously be adopted without exceeding the scope of the invention.

Having now described my invention, what I claim as new and desire to secure by Letters Patent is:

1. The combination in eddy current braking apparatus for marshalling yards of a brake winding, means for impressing an cnergizing voltage upon said winding and means for automatically reducing said voltage when a predetermined braking el'ort is attained.

2. The combination in eddy current brak ing apparatus for marshalling yards of a brake winding, means for impressing a voltage upon said winding to produce a current therein and means for automatically reducing said voltage when said current attains a predetermined value.

3. The combination in eddy current braking apparatus for marshalling yards of a brake winding, means for impressing a voltage upon said winding to produce a current therein, an impedance normally connected in circuit with said winding and means for automatically short circuiting said impedance when voltage is first impressed upon said winding.

4. The combination in eddy current braking apparatus for marshalling yards of a brake winding, means for impressing a voltage upon said winding to produce a current therein, an impedance normally connected in circuit with said winding, means for automatically short-circuiting said impedance when voltage is rst impressed upon said Winding and means for rendering said shortcircuiting means inoperative when the current in said winding attains a predetermined value.

5. The combination in eddy current braking apparatus for marshalling yards of a brake winding, an impedance connected in circuit with said winding and automatic means for rendering said impedance operative or inoperative in accordance with the current traversing said winding.

6. The combination in eddy current braking apparatus for marshalling yards of a source of alternating current, a rectifier connected to said source, a brake winding supplied with current through said rectier, a choke coil connected in circuit, between said source and said rectifier and means for controlling said choke coil automatically in accordance with the current traversing said Winding.

7. The combination in eddy current braking apparatus for marshalling yards of a brake winding, means for impressing a voltage upon said winding .to cause a current therein manually controlled means for regulating said current to control the braking eort exerted and means for automatically reducing said impressed voltage when the current traversing said winding attains a value determined -by said manually controlled means.

8. The combination in eddy current braking apparatus .for marshallin yards of a brake winding, means for supp ying energizing current to said winding, a plurality of choke coils connected in the circuit of said Winding, rnanuallly(7 controlled means for rendering said cho e coils selectively operative, and automatic means for rendering all of said choke coils inoperative until the current in said winding attains a predetermined value.

9. The combination in eddy current braking apparatus for marshalling yards of a brake winding, means for supplying current to said winding, a plurality of choke coils connected in series in the circuit of said winding, manuall controlled means for rendering said cho e coils selectively operative, a control device 'for rendering all of said choke coils inoperative when a predetermined current traverses said Winding and means controlled by said manually controlled means for regulating the operation of said control device.

AUGUST MEYER. 

